Tube annealing apparatus and method

ABSTRACT

An apparatus and method for annealing thin-walled metal tubes which comprise a body portion and a tapered shoulder portion which has a relatively thickened wall. The tubes are disposed upon a transport conveyor which rapidly moves tubes through an annealing furnace wherein a first heat source is disposed for maintaining a uniform high temperature within the chamber, and wherein a second heat source comprising a plurality of combustion flame burners are disposed within the chamber along the path of travel of the conveyor. The flame emanating from the second combustible flame burners is directed upon the shoulder portion of the tubes which are passed through the annealing furnace. The tubes are rapidly brought to the annealing temperature without rupture or deformation of the thin-walled tubes.

United States Patent McCann June 11,1974

[54] mgi g y US AND FOREIGN PATENTS OR APPLICATIONS 1,040,578 10/1958 Germany 266/5 [75] Inventor: Milton H. McCann, Wheeling, W. Primary Examiner-Roy Lake 73 Rik L M t 5 I Assistant Examiner-Paul A. Bell I 1 lgnee g g gfig nc gtrtaoney, Agent, or Firm-Parm elee, Miller, Welsh & [22] Filed: Mar. 8, 1973 [21] Appl. No: 339,357 ABSTRACT An apparatus and method for annealingthin-walled .Related Us Apphcatlon Data metal tubes which comprise a body portion and a ta- [62] l3)17v;sf:o7n815)fSer. No. 210,502, Dec. 21, 1971, Pat. No. pered shoulder portion which has a relatively thick- 1 1 v ened wall. The tubes are'disposed upon a transport conveyor which rapidly moves tubes through an an- [52] US. Cl. 26675 F, 432/2306463/gl3lg 7 Healing furnace whereina first heat Source is disposed [51] I t Cl C M for maintaining a uniform high temperature within the 158] F ld IIIIIII Q 23 Chamber, and wherein a second heat source comprisle o are 432/530 231 I ing a plurality of combustion flame burners are dis- 1 y posed-within the chamber along the path of travel of [56] R f Ct d the conveyor. The flame emanating from the second e erences l e combustible flame burners is directed upon the shoul- UNITED STATES PATENTS der portion of the tubes which are passed through the 232,882 10/1880 Bennett .l .;.432/230 annealing furnace. The tubes are rapidly brought to 6 5 F015)! 266/5'F the annealing'temperature without rupture or.defor- 2,288,008 6/1942 M85011 432/230 X- mation of thethin.walled tubes 2,795,411 6/1957 Court 432/230 2,907,858 10/1959 Distler 266/4 X 5 Claims, 3 Drawing Figures PATENTEUJUH 1 1 HM SHEET 2 OF 2 BACKGROUND OF THE INVENTION Tubular metallic containers are widely used as packaging containers in commerce. It is generally desired that the tubular metal container have a low, temper to heating or local overheating can easily result in a rupture of the tube or indistortion of the tube;

Prior art annealing furnaces typically comprise a tube supporting conveyor moving within a convective heating zone furnace within which the tubes are held for'at least several minutes to effect the annealingprocess.

SUMMARY OF THE INVENTION An apparatus and method is provided for rapidly bringing the tubular members to the annealing temperature of the metal without rupture or deformation of the thin-walled tubes. The typical thin-walled metal tubes comprise a uniform diameter body portion and a tapered shoulder portion at one end thereof, which has a relatively thickened wall. Ari enclosed heating chamber is provided with an inlet and an outlet opening, and a tube support and transport conveyor means is disposed to pass into the inlet opening and out of the outlet opening of the annealing chamber. The width of the tube support and transport means is about equal to the body'portion of the tube disposed thereon, with the shoulder portion end of the tube extending beyond one side of the conveyor means. A heat source is disposed within the annealing chamber for maintaining a uniform high temperature within the chamber. A plurality of combustion flame burners are disposed within the chamber along the path of travel of' the conveyor means, which burners are disposed to direct the flames emanating therefrom upon the shoulder portion of the tubes disposed upon the conveyor means, whereby the tubes are rapidly brought to the annealing temperature.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic representation of the tube annealing system. FIG. 2 is a partial plan view of the furnace portion of the tube annealing system.

FIG. 3 is an end view of the furnace of the tube annealing system with end wall removed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS nace. Tube support means 14 are provided on the con I3, is generally indicated.

veyor l3 and more particularly comprise a plurality of inverted V,-shaped supports 15', with" the apex of the. V transverse to the direction: of travel. of the. conveyor so that tube troughs 16 are formed between adjacent inverted V-shaped supports 15. The inverted V-shaped supports are formed of high temperature resistant metal plates with a plurality of apertures 17' therethrough. Plate burners 18- are disposed within the furnace 10 beneath the conveyor means 13. The plate burners 18 are gas fired and serve to heat the V-shaped supports 15, which have apertures 17' therein whereby the tubes 19 disposed thereon are also heated with a relatively uniform temperature being maintained within the annealing furnace 10. The tubes 19 comprise a relatively uniform diameter body portion 20 whichhas a uniform very thin wall thickness, for example of the order of about 0.003 to 0.005 inch, and a tapered shoulder portion 21 at one end of the body portion 20. The tapered shoulder portion 21 has a relatively thickened .wall, for example about 0.015 to. 0.035 inches thick.

A tube feed conveyor means 22 moves the tubes to indexing means 23, which deposits the tubes 19 upon the horizontal annealing conveyor 13 in a tube trough 16. The indexing means 23 also serves to position the tube properly upon the annealing conveyor, with the shoulder portion of the tube projecting beyond the side of the inverted V-shaped supports 15 toward the shoulder burners 24. The individual shoulder burners 24 are connected to a gas supply manifold 25.

The tubes are loaded onto the annealing conveyor 13 from a tube conveyor 22 which deposits the tubes 19 within the tube troughs 16 formed by the V-shaped supports 15. The body portion 20 of tubes 19 fits into troughs 16, with the shoulder portion 21 extending beyond the edge of the V-shaped supports 15. The plurality of combustion flame shoulder burners 24 are disposed from the side wall of the annealing furnace 10 on the same side of the conveyor 13 from which the shoulder portions 21 extend. The shoulder burners 24 are disposed to direct the flame emanating therefrom upon the tapered shoulder portion 21 of respective tubes which are passed through the annealingfurnace 10. The tubespassing out theoutletopening 12 from the annealing furnace 10 are deposited into tube holding.

which permits combusted gas to pass slowly upward V and out the stack 33. Support means 34 is provided for the conveyor 13, and drive means 35, for the conveyor The invention can be best understood by reference t a specific exemplary embodiment wherein the tubes 19 are formed of aluminum with a body portion of about nine inches long with a diameter of about 1 /2 inch, a wall thickness of about 3 thousandths of an inch, and wherein the shoulder portion extends for about 1% inches. The shoulder portion has a wall thickness of about 0.030 in. The plate burners 18 heat the high temperature resistant V-shaped supports 15 to a high tem- 3 perature which permits maintenance of a uniform tem perature distribution along the length of the tubes to insure against rupture and deformation of the thinwalled body portion when the shoulder portion is directly heated by the flames from the gas shoulder burners. The flame temperature of the combusted gas at the point where the flames from the shoulder burners impinge the tapered shoulder portion are about 2,400 to 2,600F.. The flame is preferably directed upon the underside of the tapered shoulder portion. For an annealing furnace which is about 35 inches long, preferably 17 shoulder burners are employed with the first ll burners starting at the inlet-opening being spaced about 1% ,inch apart, and with the remaining six burners spaced about 2% inches apart.

. It is possible utilizing the apparatus and method of the present invention to anneal the aluminum tubes described in about 15 seconds. This is a significant reduction in annealing time from the several minutes previously required, and yet the annealing is carried out without destructive rupturingof the very thin-walled tube and without deformation of the tube also,

The temperature of the tubes upon entering the furnace is about 100F., and in passing through the furnace in about 15 seconds the temperature of the tubes is raised to about 960F., well above the annealing temperature of the aluminum which is at least about 850F.

In summary, the present invention permits the rapid annealing of work hardened thin-wall tubes, to provide a soft, workable squeeze tube. Vast numbers of tubes must be so annealed, and the time saving had from the present invention is significant. The annealing is cardeformation or damage to the ried out rapidly without tubes.

The flamefrom the shoulder burners as can be seen in FIG. 3 is directed in the same horizontal plane in which the tubes are disposed, with the flame impinging the shoulder portion of the tube as the tube passes through the flame. The movement of the tube through the flame means that the flame is not directed continuously on one portion of the tube shoulder.

The spacing of the shoulder burners results in a succession of rapid heating periods when the flame impinges the moving tube, and conductive heating periods between burners during which the temperature of the tube tends to equalize. The shoulder burners can be more widely spaced at the exit end of the furnace because the tubes have already been raised to the proper annealing temperature, with the latter burners just 4 maintaining the tubes at this temperature.

I claim: I I

1. Apparatus for annealing thin-walled metal tubes which comprise a body portion and a tapered shoulder portion at one end thereof which has a relatively thickened wall comprising:

- a. an enclosed heating chamber having an an outlet opening;

b. a tube support and transport conveyor means which is disposed to pass into the inlet opening and out of the outlet opening, with the width of the tube supportand transport conveyor means being about inlet and equal to thebody portion of the tube disposed thereon with the shoulder portion end of the tube extending beyond one side of the conveyor means;

c. .a heat source disposed within the chamber for maintaining a uniform high temperature within the chamber;

d. a plurality of combustion flame burners disposed within the chamber along the path of travel of the conveyor means, which burnersare disposed to direct the flame therefrom upon the shoulder portion of the tubes disposed upon the conveyor means,

whereby the tubes are rapidly brought to annealing temperature without rupture or deformation of the thin-walled tubes.

2. The apparatus specified in claim 1, wherein the tube support and'conveyor means comprises inverted V-shaped supports with the apex of the V transverse to the direction of travel so that the tube troughs are formed between adjacent inverted V-shaped supports, and wherein the-inverted V-shaped supports are formed of a high-temperature resistant metal plates with a plurality of apertures therethrough.

3. The apparatus specified in claim 1, wherein the heat source comprises a plurality of plate burners disposed beneath the conveyor means.

4. The apparatus specified in claim 1, wherein the tubes are impact formed aluminum, and wherein the shoulder portion is exposed to a flame temperature of from 2,400 to 2,600F. from the combustion flame shoulder burners.

5 The apparatus specified in claim I, wherein the combustion flame burners are spaced along the length of the heating chamber, said burners being more closely spaced at the entrance end of the heating chamber.

UNITED STATES PATENT OFFICE CERTIFICATE OF C(LIRRECTION Patent Nb. 3,815,881 2' Dated une 11, 1974 Tnventoi(s) Hilton H gccann Itis certified that enfor appears in the above-idehtified patent and that said Letters Patent are hereby correctedas shown below:

In Item [73] on the face of the patent, delete as Assigned:

"Riker Lana-norms, Inc. ."Northridge, Calif."

and insez t therefor I "Muslim 3 Stamping co Signed and sealed this 5th day of November 1974.

(SEAL) Attest:

MCCOY M. GIBSON C MARSHALL DANN Attesting Officer I Commissione of Patenfps ORM PO-IOSO 10-69) uscomm-oc soavs pss Q US. GOVERNMENT PRINTING OFFICE IBI! 035 

1. Apparatus for annealing thin-walled metal tubes which comprise a body portion and a tapered shoulder portion at one end thereof which has a relatively thickened wall comprising: a. an enclosed heating chamber having an inlet and an outlet opening; b. a tube support and transport conveyor means which is disposed to pass into the inlet opening and out of the outlet opening, with the width of the tube support and transport conveyor means being about equal to the body portion of the tube disposed thereon with the shoulder portion end of the tube extending beyond one side of the conveyor means; c. a heat source disposed within the chamber for maintaining a uniform high temperature within the chamber; d. a plurality of combustion flame burners disposed within the chamber along the path of travel of the conveyor means, which burners are disposed to direct the flame therefrom upon the shoulder portion of the tubes disposed upon the conveyor means, whereby the tubes are rapidly brought to annealing temperature without rupture or deformation of the thin-walled tubes.
 2. The apparatus specified in claim 1, wherein the tube support and conveyor means comprises inverted V-shaped supports with the apex of the V transverSe to the direction of travel so that the tube troughs are formed between adjacent inverted V-shaped supports, and wherein the inverted V-shaped supports are formed of a high-temperature resistant metal plates with a plurality of apertures therethrough.
 3. The apparatus specified in claim 1, wherein the heat source comprises a plurality of plate burners disposed beneath the conveyor means.
 4. The apparatus specified in claim 1, wherein the tubes are impact formed aluminum, and wherein the shoulder portion is exposed to a flame temperature of from 2,400* to 2,600*F. from the combustion flame shoulder burners.
 5. The apparatus specified in claim 1, wherein the combustion flame burners are spaced along the length of the heating chamber, said burners being more closely spaced at the entrance end of the heating chamber. 